A few observations:
* Three of the five states with the highest combined rates are in the South (Tennessee, Arkansas and Louisiana).
* The difference between the state with the highest combined rate (Tennessee) and the lowest one (Alaska) is nearly 8 percent (7.75 percent to be exact). This doesn't account for states with no tax, of course.
* While Tennessee has the highest combined sales tax rate, it has no income tax (save for taxes on income from interest and dividends).
* Washington state has no income tax but one of the highest combined sales tax rates.